Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description must disclose behavior. It only says 'Expression discarded,' which is confusing and contradictory to 'Evaluate.' It does not explain side effects, return values, or why the parameters are unrelated. There is no useful behavioral disclosure.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely short, which is concise, but it is under-specified to the point of uselessness. It does not front-load any actionable information and fails to earn its place by adding value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with 9 parameters, no required fields, no annotations, and no output schema, the description is entirely inadequate. It does not explain what the tool does, how to call it correctly, or what the response will contain.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Even though schema description coverage is 100%, the description adds no meaning to the parameters. It claims the tool evaluates arithmetic, but none of the parameters (ref, url, city, etc.) are arithmetic expressions. The description actively misleads rather than clarifies parameter usage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Evaluate') and a resource ('a+b style arithmetic'), but it completely mismatches the input schema, which contains parameters like ref, url, city, etc. There is no arithmetic expression parameter, so the purpose is misleading. It also does not distinguish from siblings like citation or normalize-url.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool versus any of the 27 sibling tools. The description gives no context for the intended use case, and the parameter list offers no clue, so an agent cannot decide when to invoke it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.